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ALL‐trans β‐CAROTENE‐5,6‐EPOXIDE IN THYLAKOID MEMBRANES
Author(s) -
Ashikawa Ikuo,
Kito Mariko,
Satoh Kimiyuki,
Koike Hiroyuki,
Inoue Yorinao,
Saiki Kayoko,
Tsukida Kiyoshi,
Koyama Yasushi
Publication year - 1987
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1987.tb04766.x
Subject(s) - thylakoid , epoxide , membrane , chemistry , violaxanthin , spinach , xanthophyll , photochemistry , chromatography , biochemistry , photosynthesis , carotenoid , chloroplast , catalysis , zeaxanthin , gene , lutein
All‐ trans β‐carotene‐5,6‐epoxide has been found in the thylakoid membranes of spinach and of the cyanobacterium Synechococcus vulcanus Copeland. The epoxide was extracted from the thylakoid membranes with acetone, and was isolated by high‐performance liquid chromatography (HPLC). The structure of the epoxide was identified by means of mass, Raman, and electronic absorption spectroscopy. Changes in the amount of the epoxide, as a result of epoxidation and (apparent) de‐epoxidation reactions in the membranes, were traced by analysis of extracts on HPLC. In isolated thylakoid membranes, only the epoxidation reaction took place. The reaction was caused by irradiation or by the addition of ferricyanide, suggesting that electron transport reactions in the membranes are involved in the epoxidation. In intact spinach leaves, however, both epoxidation and de‐epoxidation took place; the extent of epoxidation correlated with the intensity of light incident on the leaves. The epoxidation and de‐epoxidation of all‐ trans β‐carotene are contrasted with those of xanthophylls (in the violaxanthin cycle).